The phone will unregister with the CM after 3 failed keepalive attempts. By default the keepalives are spaced 30 secs apart, which would mean that after 90 secs if the phone does not get a keepalive from the CCM it would unregister.
Likely geilsman wanted to know about media latency. Most guides recommends a max of 150ms, but you can find that you can have perfectly acceptable service with twice as much. Cisco also make additional echo cancellation hardware that can be used on the ISR gateway, VWIC2 T1/E cards. This can be be needed in high latency designs.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.